Volume 105 (2003), pp. 677–682

The authors of the above published paper have requested the following statement be made with regard to the dataset reported:

Genotyping of this dataset for other single nucleotide polymorphisms has identified two families and two siblings from a third family with incompatible genotypes. Elimination of these individuals leaves 1012 individuals drawn from 386 families (rather than 1023 individuals from 388 families). The revised results using the reduced data set (number of informative families=188) are: cTDT, z=0.91, P=0.36; and PDT, z=1.16, P=0.25.